Forrest,
For whatever reason ExpressionEngine decided this was the best way to go, you need to specify the ID of the custom field name, rather than the “short_name”
So your field names should look like this: field_id_8, field_id_9, field_id_13, etc
The easiest way to find what the actual ID number of the custom field is to view the custom fields in the CP:
CP Home › Admin › Weblog Administration › Field Groups › Custom Fields
It is NOT always the number that’s displayed beside the custom field name…
If you hover your mouse over the custom field, in the Browser where it shows the link URL, at the very end of the URL it will say ...&field;_id=6 (etc)
That is the ID of the field.
So for all custom fields, your form field will look like this (text input for example)
<input type="text" name="field_id_10" maxlength="150" />
The final step is that for EVERY custom field form field, you need to specify what the format of the field is… (matches the same for ID):
<input type="hidden" name="field_ft_7" value="xhtml" />
OR
<input type="hidden" name="field_ft_7" value="none" />
OR
<input type="hidden" name="field_ft_7" value="br" />